@ Max, what are your thoughts on
Russia's new "drone submarine" with a nuclear warhead and nuclear propulsion?
How many of these has Russia built and fielded (if any)? What naval unit is in charge of piloting them?
To me, the potential for catastrophe (e.g. loss, failure, or negligent discharge) seems greater than the potential for ever using it in a real situation.
Well, I'm retired SWO. It's better to ask a submariner. But my personal opinion - this is the thing for bullshitting you, an Americans. Having those things supposedly deployed between mainland China and Taiwan excluded every NATO presence over there like an alligator in the swimming pool. Informational A2/AD. On the other hand, once at the start of 1990s when I met Cdr Alexey Burilichev, a VADM and a deep-water boss now, while he was a CO of SSN K-461 "Wolf", I instantly concluded that he is a true leader and a man of inborn integrity. Hardly can he be in charge of some cheap farce from below the water.
So let's think logically.
1. If we have a deep submerged drone somewhere in deep ocean alone, either it has a pre-setting program (which is unthinkable given the nuke warhead - if it went crazy we will have a natural disaster, indeed), or it is controlled by some VLF way that is in long use by all major navies.
2. If you ever touched the question of VLF, you know how slow is the speed of informational flow, that is why the time required for any SSBN of any navy to get up to the launching depth just to be able to receive the keys that de-blocked the missiles via HF or satellite and then fire is about 20-25 minutes - while SSBN is at just 80 meters depth, she can receive the information at the mere speed of Morse radio-telegraph, the deeper the slower. If a drone is intended to be far below, a single piece of information to it can last a minutes while transmitted. What about the transmission from the drone by the same way? Total bull - if it is not trailing a mile-long antenna, and again, an eternity to send even short message.
3. Suppose the old sciense fiction comes true - for example, we the Russians found the way to modulate the flow of neutrino and thus to communicate to submerged subs beyond the radiofrequency realm. Russians made that and nobody in LHC in Swiss CERN is aware? Another bullshit.
4. The only way to operate that drone remotely remains - a SOFAR channel, but it means either the network of controlling stations should be installed in the ocean's floor (a kind of cellphone netting), or a mothership manned submarine should be in vicinity.
If this beast is real, I suppose a tought number 4B - a mum sub, manned one. A kind of old Japanese Kaiten carrier (look at upcoming movie "USS Indianapolis" by Nicolas Cage). Maybe not as a carrier indeed, but as a control station for several drones (a little swarm). Given the fact that Russian Navy (though not definitely Navy, the owner of them remains unclear) have at least several so-called "nuclear deepwater stations" (called "AS-xx"), it can be at least the partial answer.
Strictly for me - I think this is an information warfare booby trap, much like the Chinese DF-21N anticarrier ballistic missile. We will see.